Merge pull request #10597 from netbox-community/9072-plugin-view-tabs

#9072: Custom model view tabs for plugins

netbox/utilities/templates/tabs/model_view_tabs.html

@@ -0,0 +1,7 @@
+{% for tab in tabs %}
+  <li role="presentation" class="nav-item">
+    <a href="{{ tab.url }}" class="nav-link{% if tab.is_active %} active{% endif %}">
+      {{ tab.label }} {% badge tab.badge %}
+    </a>
+  </li>
+{% endfor %}

netbox/utilities/templatetags/tabs.py

@@ -0,0 +1,48 @@
+from django import template
+from django.urls import reverse
+from django.utils.module_loading import import_string
+
+from extras.registry import registry
+
+register = template.Library()
+
+
+#
+# Object detail view tabs
+#
+
+@register.inclusion_tag('tabs/model_view_tabs.html', takes_context=True)
+def model_view_tabs(context, instance):
+    app_label = instance._meta.app_label
+    model_name = instance._meta.model_name
+    user = context['request'].user
+    tabs = []
+
+    # Retrieve registered views for this model
+    try:
+        views = registry['views'][app_label][model_name]
+    except KeyError:
+        # No views have been registered for this model
+        views = []
+
+    # Compile a list of tabs to be displayed in the UI
+    for config in views:
+        view = import_string(config['view']) if type(config['view']) is str else config['view']
+        if tab := getattr(view, 'tab', None):
+            if tab.permission and not user.has_perm(tab.permission):
+                continue
+
+            if attrs := tab.render(instance):
+                viewname = f"{app_label}:{model_name}_{config['name']}"
+                active_tab = context.get('tab')
+                tabs.append({
+                    'name': config['name'],
+                    'url': reverse(viewname, args=[instance.pk]),
+                    'label': attrs['label'],
+                    'badge': attrs['badge'],
+                    'is_active': active_tab and active_tab == tab,
+                })
+
+    return {
+        'tabs': tabs,
+    }

netbox/utilities/urls.py

@@ -0,0 +1,39 @@
+from django.urls import path
+from django.utils.module_loading import import_string
+from django.views.generic import View
+
+from extras.registry import registry
+
+
+def get_model_urls(app_label, model_name):
+    """
+    Return a list of URL paths for detail views registered to the given model.
+
+    Args:
+        app_label: App/plugin name
+        model_name: Model name
+    """
+    paths = []
+
+    # Retrieve registered views for this model
+    try:
+        views = registry['views'][app_label][model_name]
+    except KeyError:
+        # No views have been registered for this model
+        views = []
+
+    for config in views:
+        # Import the view class or function
+        if type(config['view']) is str:
+            view_ = import_string(config['view'])
+        else:
+            view_ = config['view']
+        if issubclass(view_, View):
+            view_ = view_.as_view()
+
+        # Create a path to the view
+        paths.append(
+            path(f"{config['path']}/", view_, name=f"{model_name}_{config['name']}", kwargs=config['kwargs'])
+        )
+
+    return paths

netbox/utilities/views.py

@@ -3,8 +3,17 @@ from django.core.exceptions import ImproperlyConfigured
 from django.urls import reverse
 from django.urls.exceptions import NoReverseMatch
 
+from extras.registry import registry
 from .permissions import resolve_permission
 
+__all__ = (
+    'ContentTypePermissionRequiredMixin',
+    'GetReturnURLMixin',
+    'ObjectPermissionRequiredMixin',
+    'ViewTab',
+    'register_model_view',
+)
+
 
 #
 # View Mixins
@@ -122,3 +131,75 @@ class GetReturnURLMixin:
 
         # If all else fails, return home. Ideally this should never happen.
         return reverse('home')
+
+
+class ViewTab:
+    """
+    ViewTabs are used for navigation among multiple object-specific views, such as the changelog or journal for
+    a particular object.
+
+    Args:
+        label: Human-friendly text
+        badge: A static value or callable to display alongside the label (optional). If a callable is used, it must accept a single
+            argument representing the object being viewed.
+        permission: The permission required to display the tab (optional).
+    """
+    def __init__(self, label, badge=None, permission=None):
+        self.label = label
+        self.badge = badge
+        self.permission = permission
+
+    def render(self, instance):
+        """Return the attributes needed to render a tab in HTML."""
+        badge_value = self._get_badge_value(instance)
+        if self.badge and not badge_value:
+            return None
+        return {
+            'label': self.label,
+            'badge': badge_value,
+        }
+
+    def _get_badge_value(self, instance):
+        if not self.badge:
+            return None
+        if callable(self.badge):
+            return self.badge(instance)
+        return self.badge
+
+
+def register_model_view(model, name, path=None, kwargs=None):
+    """
+    This decorator can be used to "attach" a view to any model in NetBox. This is typically used to inject
+    additional tabs within a model's detail view. For example, to add a custom tab to NetBox's dcim.Site model:
+
+        @netbox_model_view(Site, 'myview', path='my-custom-view')
+        class MyView(ObjectView):
+            ...
+
+    This will automatically create a URL path for MyView at `/dcim/sites/<id>/my-custom-view/` which can be
+    resolved using the view name `dcim:site_myview'.
+
+    Args:
+        model: The Django model class with which this view will be associated.
+        name: The string used to form the view's name for URL resolution (e.g. via `reverse()`). This will be appended
+            to the name of the base view for the model using an underscore.
+        path: The URL path by which the view can be reached (optional). If not provided, `name` will be used.
+        kwargs: A dictionary of keyword arguments for the view to include when registering its URL path (optional).
+    """
+    def _wrapper(cls):
+        app_label = model._meta.app_label
+        model_name = model._meta.model_name
+
+        if model_name not in registry['views'][app_label]:
+            registry['views'][app_label][model_name] = []
+
+        registry['views'][app_label][model_name].append({
+            'name': name,
+            'view': cls,
+            'path': path or name,
+            'kwargs': kwargs or {},
+        })
+
+        return cls
+
+    return _wrapper